1. Field of the Invention
The present invention relates to an optical scanner apparatus and an optical scanner control apparatus.
2. Description of the Related Art
Conventionally, an optical scanner apparatus in which a mirror portion which reflects an input light is rotated around a rotational axis by an actuator including a lower electrode, a piezo-electric element and an upper electrode formed in this order to scan the reflected light is known. By this actuator, the mirror portion is oscillated in vertical and horizontal directions with respect to a reflection surface by applying driving voltages to the upper electrode and the lower electrode.
Further, in this optical scanner apparatus, a piezo-electric sensor for detection which detects a voltage generated in the piezo-electric element of the actuator while the mirror portion is being oscillated is further provided. An inclination of the mirror portion is detected by an output of the piezo-electric sensor for detection so that the operation of the actuator is controlled.
The voltage detected by the piezo-electric sensor for detection may be interfered by a noise as the voltage detected by the piezo-electric sensor for detection when the mirror portion is being oscillated is very small. Thus, various techniques have been developed to appropriately detect the voltage by the piezo-electric sensor for detection.
For example, Patent Document 1 discloses a technique in which an electrode of the actuator and an electrode of the piezo-electric sensor for detection are formed to be apart from each other. With this structure, it is described in Patent Document 1 that the grounded voltages for the actuator and the piezo-electric sensor for detection can be separated and the interference of the noise caused by the grounded voltage of the actuator to the voltage detected by the piezo-electric sensor for detection can be avoided.
However, according to the conventional technique, the voltage detected by the piezo-electric sensor for detection is very small and is easily interfered by a noise (crosstalk) from other signal lines. Thus, there is a possibility that an inclination of a mirror cannot be precisely detected because of the noise (crosstalk).